Circuit arrangement for automatic telephone systems



March 10, 1931. M. LANGER 1,

cmcux'r ARRANGEMENT FOR AUTOMATIC TELEPHONE SYSTEMS Filed Aug. 12, 1927Im ren u1" Flax L er' to 04 are operated.

Patented Mar. 10, 1931 UNITED s r MAX LANGER, or HEB-Mellow", NEAR-BERLIN, GERMANY; Assrcnon TO SIEMENS &

I-IALSKE AKTIENGESELLSCHAFT, OF WERNERWEBK, SIE MENSSTADT, NEAR BER-LIN, GERMANY CIRCUIT ARRANGEMENT FOB AUTOMATIC TELEPHONE SYSTEMSApplication filed. August 12, 1827, Serial No.

In automatic telephone systems a certain and faultless emission ofcurrent impulses is dependent to a large extent on the switching timesof the impulse-storing relay. Known already are arrangements in whichthe impulse storing relay is connected in a more sensitive circuitduring the sending out of impulses. With such arrangements however oneof the switching periods of the relay is unfavorably influenced.

The purpose of the invention is to bring about that with each conditionof energization of the relay the switching time necessary for obtainingthe other condition of energization shall be curtailed and this isaccomplished by the impulse-storing relayso acting upon, its own circuitthat with each state of energization (either energized or deenergized)there is present a condition of-current which is adapted to bring abouta rapid attainment of the other condition ofener- 'gization.

The drawing shows an example ofthe invention inthe form of the circuitof a group selector. Assuming that the group selector has been engagedby any switching device allotted to it, then the relay 0 will beenergized. Consequently the contacts 01 The contact 01 connects thewinding II of the relay G to the 0 wire. The contact 02 applies earth tothe circuit for the lifting magnet H. The latter however is notenergized because, during the en-' gagement of the group selector theline relay A and the release relay B at the lines a and b are energized.The energizingcircuit for the relays A and B runs from battery, windingof the relay A, a-wire, over the preselecting member (not shown),subscribers loop to the 7) wire, winding Tl of the relay B, contact a2,of the relay B, earth. The relay B through its contact 61 opens theshort circuit of the winding 11 of the relay C. Relay A opens, throughits contact (11 the circuit for the lifting magnet H. If, by using hisdial switch, a subscriber sends out a series of impulses, then during afirst interruption of the loop the relay A will be made to retract;since the contact a2 is open when the relay A is energized, the latterrap- 212,456, and in Germany January 31, 1927.

such a kind that the relay A responds con-' siderably more rapidly thanif the winding I of the relay B were not short circuited. During theenergization of the lifting magnet H the relay V is maintained energizedover its winding II, theshort circuit around its winding I renderingrelay V slow-acting,

wherebythe circuit of the rotary magnet D is maintained opened throughthe contact o1. If the switching arms of the group selector arepositioned on the desired tens level, the relays Aand B are energized atthe end of the impulse sending so that the relay V is made to retract.During the first lifting step of the selector the closing of theoil-normal contact 701 took place, so that the following circuit iscompleted for the rotary magnet D during the retraction of the relay Vafter theimpulse series has been sent out by the subscriber: earthcontact J01, contact p1, leftcontact of the double acting contact o1,winding of the rotary magnet D,- battery. The rotary magnet D isenergized and actuates its contact cl, whereby an ener-. gizingcircuitis established for the relay V a which runs from the battery over thewind-* ing of the liftingmagnet H. winding of thc relay V, closed 03contact, off-normal contact 731, earth. Since, duringthe first rotarystep of the selector, the contact '10 had been opened,

the resistance of the relay V in relation to the resistance of thewinding of the lifting magnet H is of such a kind that the liftingmagnet H is not energized in this circuit. By

energizing the relay V the double acting contact '01 is opened. and thusthe circuit'for the rotary magnet D is interrupted. The rotary magnet'Dis de-energized and through its contact cl opens the circuit for therelay V. The latter, upon retracting, closes the contact 01 whereby thecircuit for the magnet D is again closed. This alternate action betweenthe relay V and the magnet D is continued until the testing arm of theselector has found a free line. If the testing arm finds battery overthe outgoing line 0 the relay P is made to energize and opens thecircuit for the rotary magnet I) through its contact p1. The contact72?. applies earth to the winding I of the relay P. The contacts p3 andp 1 switch the connection through.

If the connection is to be released the calling subscriber hangs up hisreceiver whereby the relays A and B are made to retract. The relay Acloses the contact a2 and thereby again establishes the currentconditions adapted to cause the relay A to function. Through its contact51 the release relay B short circuits the winding II of the relay C sothat the latter is made to retract as the off-normal contact 702 hasalready cut oil tl e winding I of the relay C from earth, during thefirst lifting step of the selector. 'lhrough contact 04 the winding ofthe relay P1 is short circuited so that the latter is de-energized.Consequently contact p1 is closed and the rotary magnet is energizedover earth, contact 701, contact 791, left contact at the double actingcontact 111, winding D of the rotary magnet, battery. The rotary magnetnow moves a step and actuates its contact (Z whereby a circuit for therelay V is completed over: earth, off-normal contact 7.:1, double backcontact (I, windings I and II of the relay V, winding H of the liftingmagnet H, battery, earth. In this circuit the lifting magnet- H does notrespond. However, the relay V is energized and actuates its contact o1whereby the double acting contact is opened and the retary magnet D ismade to de-energize. Thus, in this manner, the switching arms of thegroup selector are rotated until they reach their extreme rotaryposition, thereby causing the switch to release in known manner and opencontact 721 and close contact 702. Through the retraction of the relay Pthe switching devices which have been taken into use by the selector GVVare released in any known manner.

hat is claimed is:

1. In a telephone system, an impulse responding relay, a release relay,a circuit for said relays including a source of current, means forinterrupting said circuit to deenergize and energize said impulseresponding relay, and means controlled by said impulse responding relayin either its onergized or deenergized positions for chang ing the saidcircuit so as to enable said impulse responding relay to rapidly attainits energized or deenergized position as the case may be, said meansbeing-effective also to render said release relay slow acting.

2. In a telephone system, an impulse "respending relay, asecond 'rel'ayhaving two windings, a trunk line, a battery for talking and operatingpurposes, an energizing circuit for said relays including one pole ofbattery, the winding of said impulse relay, the two sides of said trunkline, one winding of said second relay, and the opposite pole of batteryin series, and contacts on said impulse relay operated responsive to theenergization of said impulse relay for including the second winding ofsaid second relay in said energizing circuit to reduce the current flowin said circuit to enable said impulse relay to more rapidly deenergizewhen said circuit is opened.

3. In a telephone system, a two conductor subscribers line extending toan automate switch, a battery,a line relay in said switch connectedbetween one conductor of said line and one pole of said battery, animpedance in said switch connected between the other conductor of saidline and the other pole of said battery, a circuit for shunting saidimpedance, and contacts on said line relay included in said circuit.

I. In a telephone system, a two conductor subscribers line extending toan automatic switch, a battery, a line relay connected between oneconductor of said line and one pole of said battery, a double woundrelay connected between the other conductor of said line and the otherpole of said battery, one winding of said double wound relay beingnormally short-circuited, and contacts on said line relay for openingthe short-circuit around said winding to increase the impedance of saiddouble wound relay when said line relay is energized.

In witness whereof, I hereunto subscribe my name this 19th day of July,A. D. 1927.

MAX LANGER.

